Performance of Newer Breakers Based on Time to First Corrective Maintenance

Figure 2-1 shows Kaplan-Meier plots of the time to first CM for two specific breaker families; The colors mark the performance of these families at five different utilities. The populations of the different families vary among the utilities. The plots illustrate the different maintenance requirements of the families and reveal another insight: the performance of these families over this observation period is independent of the utility in which they are installed. It is quite reasonable to say that the circuit breaker performance in regard to need for maintenance in the first ten years is independent of how the breaker is used or maintained at a utility. In other words, it is an intrinsic characteristic of the breaker design. As shown in Figure 2-1, breaker families tend to behave similarly for first corrective maintenance (CM) requirements for younger breakers (< 10 years) at multiple utilities. The figure also shows that the spring breakers have a shallower slope than the hydraulic breakers. This indicates the hydraulic mechanisms require earlier CM compared to the spring breakers. Similar plots can be created for all the gas breakers, or families can be compared across utilities for benchmarking purposes.